"Nothing" refers to the absence of anything; it is the state of non-existence. In philosophy, it raises questions about existence and reality, prompting discussions about what it means for something to be present or absent. In everyday language, "nothing" can describe a lack of substance or value, such as when someone says, "There is nothing in the box." In mathematics, "nothing" can be represented by the number zero, which signifies a null quantity. Overall, "nothing" is a concept that challenges our understanding of existence and perception.